78 B. TV. Bull on Emulsine and its Composition. 



est degree, and apparently to an equal extent. The presence of 

 foreign substances injures this reaction, and even the presence of 

 a small amount of alcohol or acetic acid prevents it altogether. 



The property of being precipitated by alcohol does not belong 

 to emulsine in itself, and this method of its preparation and pre- 

 cipitation from the other substances rests upon the phosphates 

 which are held in solution by it, and they have so much affinity 

 for each other, that I have not succeeded in separating emulsine 

 from these inorganic substances without destroying its property 

 of decomposing amygdaline. Emulsine has a decidedly acid reac- 

 tion. When washed out with alcohol till the latter comes away 

 entirely neutral, the moist emulsine reddens litmus strongly ; dried 

 emulsine is also acid when redissolved. To this acid property is 

 owing the presence of the earthy phosphates in the almond emul- 

 sion, and to their insolubility in diluted alcohol and simultaneous 

 affinity for emulsine, must be ascribed the cause of the precipitation 

 of the latter by the addition of alcohol. In proof of the preced- 

 ing remarks, the following may be mentioned. I neutralized an 

 emulsion of almonds by means of a careful addition of lime water, 

 which precipitated the phosphates entirely. The filtrate did not 

 contain a trace of phosphoric acid, reacted in a marked man- 

 ner with amygdaline, but was not precipitated by alcohol Am- 

 monia acts in the same way. The liquid becomes cloudy indeed, 

 on the addition of alcohol, but it is not cleared by filtration, and 

 only after several days does a scarcely appreciable precipitate ap- 

 pear. A solution of emulsine neutralized in this way, if left by 

 itself, exposed to the ordinary temperature of summer, commences 

 to decompose in a few days, and assumes a disagreeable odor ; the 

 liquid becomes turbid, deposits, but does not again acquire an 

 acid reaction. 



Emulsine is not coagulable by heat. A solution of it becomes 

 cloudy at a temperature of 35° to 36° C, at 45° it is quite opaque 

 and milky, and at 85°-90° deposits a snow-white granular sub- 

 stance. When exposed to the heat of a water bath even a num- 

 ber of hours, the filtrate on additional heating still continues to 

 deposit, but if the liquid is carefully heated over a flame to the 

 boiling point and maintained at that temperature a few moments, 

 the filtrate possesses the singular property, upon again being heat- 

 ed to ebullition, of becoming quite opaque, with separation of 

 bulky flocculent masses, which perfectly redissolve upon cooling, 

 and the liquid becomes as clear and limpid as before. The re- 

 peated action of heat is followed by the same result; the floccu- 

 lent matter redissolving perfectly, after being produced several 

 times. The granular precipitate which is formed amounts to 

 about ten per cent, of the emulsine employed. It is perfectly 

 white, easily reduced to a fine light powder, and leaves a neutral 

 ash, amounting in one instance to 4874 per cent., and in another 



